Re: grub2-probe confused by double bind mount?

[Chris Murphy]

It's not the double bind mount. I've removed it by eliminating the -o
subvol option and adjusted paths accordingly during assembly. But
grub2-probe still fails inside the chroot, even though it works on the
path I'm chrooting.

mount assembly
https://pastebin.com/LMSPeeiP

strace grub2-probe inside chroot (fails)
https://pastebin.com/S1mA8RTh

strace grub2-probe outside chroot (succeeds)
https://pastebin.com/VkfZnsKu


In the outside chroot (working) case, line 233 it figures out it's
Btrfs with Btrfs specific ioctls. Where the failing case never does
even after digging around in /dev/ which it does find and yet
complaint that it's not mounted. So the error message itself seems
bogus and only a symptom of confusion and not what or why the actual
problem is happening.

The non-working case looks like it starts failing after line 213,
openat /proc/self/mountinfo as if whatever it finds there is not at
all helpful.

inside
< 693 225 0:6 / /dev rw,nosuid shared:22 - devtmpfs devtmpfs
rw,seclabel,size=3999060k,nr_inodes=999765,mode=755

outside
> 21 71 0:6 / /dev rw,nosuid shared:22 - devtmpfs devtmpfs 
> rw,seclabel,size=3999060k,nr_inodes=999765,mode=755


Chris Murphy